To the math, you'd be well served by "Rocket Propulsion Elements" by
Sutton https://amzn.to/3nKyiWV and, to a lesser degree, "Modern
Engineering for Design of Liquid Propellant Rocket Engines" usually
known as Huzel&Huang. The latter is available as a PDF in an older
version when it was a Nasa document. (Likely both are available as
PDFs of modern versions, because it's the internet.)
They are mostly focused on liquid rockets but there's plenty of
overlap into your half-liquid rocket. Looking on Amazon I do see "The
science and design of the hybrid rocket engine"
https://amzn.to/38FWIMU and "Fundamentals of Hybrid Rocket Combustion
and Propulsion" https://amzn.to/2XKJojX , the first looks
self-published and the latter is more traditional AIAA; probably the
first one would be more immediately useful to you just starting.
The most common failure I've seen of people just getting into small
liquid or hybrid rockets is messing up the sizing such that the
chamber runs at too low of a pressure to achieve choked flow, thus
making it a torch (or charitably a gas generator) rather than a
rocket. This can be detected easily by a chamber pressure sensor, but
that is rare; it can be detected visually and acoustically by a lack
of mach diamonds in the exhaust.
For example, this is not a rocket engine despite the statements and
high production value: https://www.youtube.com/watch?v=VI8gdmjEwKc
Same situation here, despite Ben Krasnow being generally a genius
otherwise: https://www.youtube.com/watch?v=TLPWqCMb7DE
And again: https://www.youtube.com/watch?v=c9YRRQ9f7v4
Here's one that's actually rocketing:
https://www.youtube.com/watch?v=pDzsNhUeS4s Note the shape and length
of plume and visible mach diamonds.
Generally, if you can stand to be in a room with it without ear
protection then it's not a rocket engine.
On Wed, Jan 13, 2021 at 6:59 PM Jack Hanna <jackhannaofficial@xxxxxxxxx> wrote:
Hello!
So I've been occasionally popping into here to ask questions about a hybrid
nitrous oxide + paraffin mixed with carbon black engine. I've gotten a good
idea of what I want to do with the engine, but now since I finally have a job
and some disposable income I can start buying things and actually make a
schematic of a design.
So, how to math?
I know NASA had some site that has a very in depth calculator for some sort
of either ISP / thrust / fuel or something, but it's broken as far as I can
tell and I don't know of any alternatives. I think it would be better to do
more math and get a more specific design set out as i'm not going to be
building this for a while anyways, as I still lack access to a lathe and mill
due to coronavirus.
In the meantime, there was an email about a dirt simple DIY nitrous rocket
that somebody had sent to me, and it looks like a fun project to just get a
toe in the water when it comes to rocketry so I know how to deal with engines
and what's safe and just get a feel for them, so i'm wondering what are some
best practices for nitrous oxide handling, and what i would need for a simple
plumbing system that would run a tiny ~4inch rocket. If possible I would also
love a design that mimics what I would require for my hypothetical rocket so
far, that being the nitrous. If anyone has any good resources, that would be
absolutely wonderful. An overkill setup would ideally be perfect as the best
thing I can think of is a very "boring" static fire.
I'm just getting into physics and calculus now, but I don't particularly
think that the equations would be too complicated, and if they were, I think
I can work through them or ask one of my teachers for help.
Thanks so much for all the help, ya'll been a great help.